In many of the passive safety restraint systems presently being developed for automotive vehicles, it is contemplated to mount vehicle sensitive seat belt retractors in or on the doors. These retractors are responsive to accelerations in any direction as low as 0.7 G's to prohibit the extraction of the webbing from the retractor's spool. Unfortunately, the acceleration of the vehicle's door when it is opened often exceeds this value and will lock-up the retractor preventing the door from being fully opened. To prevent this problem, the prior art teaches the use of cables and/or mechanical linkages to lock-out the retractor's acceleration or crash sensor when the door is open. These cables and mechanical linkages are bulky, costly and require the operator to supply the added energy necessary to lock-out the retractor.
The lock-out actuation is normally provided by a spring loaded plunger producing a mechanical displacement when the door is opened. This is similar to the plunger which releases the retractor's tension relief mechanism when the door is opened permitting the retractor to retract the loose seat belt webbing. These mechanical devices normally require the door to be opened a distance beyond the safety latch position before the retractor is lock-out, otherwise, the retractor would be locked-out when the door is being retained in the closed position by the safety latch. Therefore, the mechanical lock-out devices require a significant opening displacement of the vehicle's door before the retractor is locked-out.
This required initial opening displacement of the vehicle's door is unsatisfactory because accelerations experienced by the door when the seal is broken and before the mechanical plunger is actuated are sufficiently high to lock-up the retractor.
This invention is an electrical lock-out device for door mounted vehicle sensitive seat belt retractors is responsive to the unlatching of the door's mechanical locking mechanism which overcomes the problems discussed above.